Means of illuminating telephone dials, etc.



Dec. 26, 1944. H. E. CHAPMAN MEANS OF ILLUMINATING TELEPHONE DIALS, ETC

7 Filed March 25, 1942 C ATTORNEY 7 ,Patented 26 1944 Y UNITED MEANS OFILLUMINATIN G TELEPHONE DIALS, ETC.

3 Claims.

This invention relates to illuminatingv telephone dials, radio dials,pressure indicators, speed indicators, or other types of indicatinginstruments,

-where illumination is not sufficient for proper visibility, by means ofusing a clear transparent plastic material or other characteristicmaterial,

as a light transmitting medium without projecting undesirable lightoutside the instrument itself.

This lllumination is obtained by projecting light from a small electriclamp into the inner mass ofthe clear transparent plastic material, orother characteristic material, hereinafter referred to as plasticmaterial, which is placed directly over the face of the instrument, orsub- .stituting the plastic material forthe engraved dial of theinstrument and by means of having the engraving appearing on the plasticmaterial.

This invention makes use of the fact that the plastic---material will inturn transmit the light throughout its entire mass, making thecharacters engraved on the face of the dial or instrumentclearlyvisible.

My invention will be more fully understood from thespeciflcationhereinafter followin by reference to the accompanying drawing in which:

Figure l is a plan view of a telephone dial to which my invention isapplied; Fig. 2 is a transverse sectional view taken on line'2-2 of Fig.3 and illustrating in plan the device of my invention applied to atelephone dial; Fig. 3 is a sectional' view taken through the device ofmy invention as applied to a telephone dial substantially on line 3-3of'Fig. 1; Fig. 4 is a sectional view through the device of my inventionshowing the construction of the device for general application to dialsfor various instruments; and Fig. 5 is a theoretical diagram showing thesystem of light distribution provided by the device of my inventionapplied to dials of various arrangements.

In the drawing, reference character a represents a disc orring ofplastic material, this ring of plastic material is the subject of thisinvention. Reference character 2 designates a thin film or layer of bluetinted plastic (with a small section'cut away in Fig. 5 to indicate itspresence) glued, cemented or vulcanized on the entire surface of theface of the plastic ring i to further prohibit undesirable light outsidethe instrument and still permit the engraving on the dial to be clearlyvisible. Reference character 3 designates a circular opening to permitthat part of a telephone dial which extends above the dial number plateto extend through the plastic material to allow it to fit evenly andflush with the dial plate. Reference character d indicates a smalleropening in the plastic. material l to permit a small electric lamp D toextend to or through the plastic material I The wall of this opening tis highly polished to permit all the light possible to be admitted tothe inner mass of the plastic material l. Reference character tdesignates a small metallic or non-transparent plate to fit over openingt to prohibit direct light from the lamp being projected outside theinstrument. Reference character i indicates two small pins permanentlymounted on plate t to facilitate mountii'ig the plate upon the plasticmaterial. These small pins are slotted on their outer end to provide atension on the walls of holes 5, which are drilled in the plasticmaterial 2! on either side of opening t to hold the plate t in place.The plate 6 is mounted in such manner to enable the lamps to be easilyreplaced. The walls of the circular opening 3 and the outside walls ofplastic material 5! as indicated in Fig. 4, at reference character 8are-treated to prohibit undesirable light from escaping from the plasticmaterial at these points.

Fig. 4 is a cross sectional view of'Fig. 1 showing the lightdistribution device of my invention adapted for general application todials of various descriptions. ihe device is toroidal in shape and willreadily lit with one face thereof directly against the dial. The lightreflective surfaces 8 are applied to the inner and outer peripheraledges of the device as heretofore explained and a light modifying filmor layer 2 is provided over the opposite face of the device asheretofore ex-' plained.

Figs. 1, 2 and 3 illustrate the use of this invention in connection witha telephone dial, the letters in the illustration referring to variousparts of the dial are used to clarify the illustration and are not apart of the invention, but the figures used to identify various parts ofthe illustration are a part of the invention.

Letter A, Fig. 3, designates the shellor case of a telephone dial,letter B designates the dial plate which carries the engravingidentifying the steps of rotation of the finger wheel C, letter Ddesignates a small electric lamp projecting through a hole cut in-thedial plate to coincide with the opening 4, Figs. 3, 4, 5, to act as anilluminating medium. Letter E designates the rotating shaft of the dialupon which the finger wheel C is mounted. In Fig. 2 the finger wheel isomitted to better show a faceview of this invention as used with atelephone dial.

In Fig. 3 the plastic material is identified by reference character I,the necessity of the opening identified as number 3 in Fig. 2 is clearlyshown. Fig. 3 shows the lamp opening number 4 and the cover plate number6 as being located under that portion of the finger wheel where nofinger, hole punchings appear. The lamp D derives its operating currentdirectly from the telephone line and becomes lighted as the telephonereceiver is taken from the switchhook and remains lighted as long as thereceiver is oil the switchhook.

What I claim and desire to secure by Letters Patent 01 the United Statesis as follows:

1. Means for illuminating a dial comprising a circular dial having anannular row of identifying characters carried thereon, a fiat ring oflight distributing plastic material having a light transmitting facepositioned adjacent the annular row of identifying characters on thedial, a light modifying film extending over the opposite face of saidring, light opaque means extending over the inner and outer edges ofsaid ring, means extending through a portion of said ring forintroducing light rays into the body of said plastic material, and acover member engageable with a portion of said flat ring for obstructingdirect emanation of light rays from said ring.

2. Means for illuminating a dial comprising a circular dial having anannular row of identifying characters carried thereon, a toroidal memberof light distributing plastic material having a light transmitting facepositioned adjacent the annular row of identifying characters on thedial. alight modifying coating on the opposite face of said member,light reflecting means covering the inner and outer peripheries of saidmember, a light source extending through a portion of said member forilluminating the interior of said member by disseminating light raysthrough said member by reflection from said light reflecting means, anda cover for housing said light source removably engaging a portion ofsaid toroidal member.

3. Means for illuminating a dial comprising a circular dial having anannular row of identifying characters carried thereon, a toroidal memberof light distributing plastic material having a light transmitting facepositioned adjacent the annular row of identifying characters on thedial, a light modifying coating on the opposite face of said member,light reflecting means covering the inner and outer peripheries of saidmember, a light source extending through a portion of said member forilluminating the interior of said member by disseminating light raysthrough said member by reflection from said light reflecting means, anda disc-like light opaque device removably engageable with a portion ofsaid toroidal member for confining the light rays from said light sourceto the body structure of said toroidal member.

HARRY EDWIN CHAPMAN.

